/*
 * Copyright 2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.influxdb;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;

import lombok.extern.slf4j.Slf4j;

@Slf4j
final class ConverterUtils {
	public static boolean isBlank(final CharSequence cs) {
		final int strLen = length(cs);
		if (strLen == 0) {
			return true;
		}
		for (int i = 0; i < strLen; i++) {
			if (!Character.isWhitespace(cs.charAt(i))) {
				return false;
			}
		}
		return true;
	}

	public static int length(final CharSequence cs) {
		return cs == null ? 0 : cs.length();
	}

	public static List<Field> getFields(final Class<?> cls) {
		final List<Field> allFields = new ArrayList<>();
		Class<?> currentClass = cls;
		while (currentClass != null) {
			final Field[] declaredFields = currentClass.getDeclaredFields();
			Collections.addAll(allFields, declaredFields);
			currentClass = currentClass.getSuperclass();
		}
		return allFields.stream().filter(field -> isNonAccess(field)).collect(Collectors.toList());
	}

	private static boolean isNonAccess(Field field) {
		int mod = field.getModifiers();
		if (Modifier.isTransient(mod) || Modifier.isFinal(mod) || Modifier.isStatic(mod)) {
			return false;
		}
		return true;
	}

	public static Object readField(final Object orig, final Field field) {
		try {
			field.setAccessible(true);
			return field.get(orig);
		} catch (IllegalAccessException e) {
			log.warn(e.getMessage());
			return null;
		}
	}
}
